From the Richmond Sentinel, 4/15/1863, p. 2, c. 2

Broke Jail. – On Monday night, two prisoners effected their escape from the county
jail, and, we believe, are yet at large. One of them is the notorious Tim
O’Brien, who was arrested not long ago in the act of presenting a forged check
for payment at the Treasury Department. Extra preparations were made for his
security at the time of his incarceration, but it seems Tim was too much for his
vigilant custodians. Five prisoners made their escape from the military prison
called Castle Thunder, a day or two since.